FifoRecorder: Don't allocate ~100.7MB on program startup

So, a FifoRecorder instance is instantiated as a file-local variable and
used as a singleton (ugh). Most users likely don't regularly use the
FIFO player/FIFO recorder, so this is kind of a substantial waste of
memory.

FifoRecorder's internal RAM and ExRAM vectors are 33554432 and 67108864
bytes respectively, which is around 100.66MB in total.

Just on the game list view on a clean build with nothing loaded, this
knocks debug build memory usage down from ~232.4MB to ~137.5MB, and
release build memory usage down from ~101MB to ~5.7MB.

Source/Core/Core/FifoPlayer/FifoRecorder.cpp

@@ -18,9 +18,7 @@
 static FifoRecorder instance;
 static std::recursive_mutex sMutex;
 
-FifoRecorder::FifoRecorder() : m_Ram(Memory::RAM_SIZE), m_ExRam(Memory::EXRAM_SIZE)
-{
-}
+FifoRecorder::FifoRecorder() = default;
 
 FifoRecorder::~FifoRecorder()
 {
@@ -36,6 +34,22 @@ void FifoRecorder::StartRecording(s32 numFrames, CallbackFunc finishedCb)
   FifoAnalyzer::Init();
 
   m_File = new FifoDataFile;
+
+  // TODO: This, ideally, would be deallocated when done recording.
+  //       However, care needs to be taken since global state
+  //       and multithreading don't play well nicely together.
+  //       The video thread may call into functions that utilize these
+  //       despite 'end recording' being requested via StopRecording().
+  //       (e.g. OpcodeDecoder calling UseMemory())
+  //
+  // Basically:
+  //   - Singletons suck
+  //   - Global variables suck
+  //   - Multithreading with the above two sucks
+  //
+  m_Ram.resize(Memory::RAM_SIZE);
+  m_ExRam.resize(Memory::EXRAM_SIZE);
+
   std::fill(m_Ram.begin(), m_Ram.end(), 0);
   std::fill(m_ExRam.begin(), m_ExRam.end(), 0);